1. Field of the Invention
Embodiments of the present invention relate to an electronic instrument and, in particular, embodiments to an electronic instrument in which an analog signal that is modulated by a digital signal is input, is demodulated, and fed to a sound source.
2. Description of the Related Art
For some time electronic instruments have been known in which Musical Instrument Digital Interface (MIDI) data, which is data that conform to the MIDI standard, (a standard for performance data that carries out instructions such as the starting or stopping of the production of musical tone signals mutually between electronic instruments or between an electronic instrument and a personal computer), is input and a musical tone signal is generated in conformance with the inputted MIDI data. For example, an electronic instruments that conforms to the MIDI standard is disclosed in Japanese Laid-Open Patent Application Publication (Kokai) Number 2002-297132.
In addition, in Japanese Laid-Open Patent Application Publication (Kokai) Number 2004-233416, an electronic instrument is disclosed in which the frequency or the frequency band of an audio signal that has been reproduced using a compact disc (CD) is detected as required and the key of the pitch that corresponds to the frequency or the frequency band that has been detected is pressed down.
In addition, an electronic instrument is presented in which one or the other of the analog signals of the left and right audio channels reproduced by a CD or a digital versatile disc (DVD) and the like is modulated by a digital signal (the MIDI data) and stored. The digital signal is demodulated from the analog signal and converted into MIDI data. The musical tone is produced by driving the keyboard of a piano. The analog signal of the channel which is not modulated by the digital signal is reproduced as a musical accompaniment of the musical tone that is produced by driving the keyboard.
However, problems can be encountered with an electronic instrument in which one or another of the analog signals of the left and right audio channels of a CD and the like is modulated by a digital signal and stored, where this analog signal is demodulated to produce a digital signal that controls a keyboard. For example, whether or not the analog signal is modulated by the digital signal that controls the instrument must be confirmed referring to the CD or to the instruction book that is attached to the CD. The electronic instrument must be set by an operation to either simply reproduce the CD or to control the electronic instrument based on the analog signal that has been modulated and stored in one or the other channel.
In addition, since one of the two left and right channels that are reproduced, on which channel the analog signal is modulated by the digital signal that controls the instrument is different depending on the type of CD and the like, there has been the drawback that it is necessary to make the settings of that type in accordance with the operation. In those cases where the user makes a mistake in the connection with the left and right input channels, the intended operation of the electronic instrument will not be achieved.
In addition, in the past, a reproduction system has not existed with which images and audio signals that have been stored on a DVD and the like are reproduced, where the digital signal like the MIDI data that controls the electronic instrument is demodulated from the audio signal, the electronic instrument is controlled by the control signal that has been demodulated, and the images and musical tones that have been generated by the electronic instrument are synchronized and reproduced.